Removable collar for matching high frequency impedance and high frequency cable television using the same

ABSTRACT

A cable television device with high frequency impedance matching includes a housing and a removable collar. The removable collar is disposed on a signal inputting port or a signal outputting port of the housing and a cable wire is connected to the signal inputting port or a signal outputting port. When a high frequency is inputted, the impedance of the removable collar is substantially close to the impedance of the cable wire to reduce the reflected amount of the transmitting signal and the attenuation of the transmitting high frequency signal.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a high frequency cable television device, and in particular to high frequency cable television having a property of matching high frequency impedance.

2. Description of Prior Art

Cable television signals transmitting in the conventional cable television is split by a video splitter and separately transmitting to different buildings or communities so that the residents in the buildings, communities or companies can receive signals and watch cable television programs.

Because the frequencies of transmitting signals of the conventional cable television becoming higher and higher, and the signal is usually attenuated in the transmission process, the image quality showed in the television of the client end becomes worse. The main reason is due to high frequency impedance mismatched. If high frequency matching is desired, the loading impedance must be equal to or approximate to the impedance of the cable wire during the signal transmission process, and the reflecting amount of the transmitting signal is also reduced.

Therefore, a signal inputting port (or signal outputting port) 101 of the conventional cable television device 10 (shown in FIG. 1) is connected to a cable wire 20. The cable wire 20 includes a core wire 201, a joint 202 and a signal transmitting terminal 203. The signal transmitting terminal 203 is plugged into the signal inputting port 101 and a conductive pin 301 of a conductive bridge set 30. A space 40 is formed between the joint 202 and the conductive bridge set 30 so that the impedance between the joint 202 of the cable wire 20 and the conductive bridge set 30 is mismatched and the transmitting signal is reflected. As a result, the transmitting signal is attenuated and the image quality becomes worse.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides a removable collar. The removable collar is disposed between a signal inputting port or a signal outputting port and a conductive bridge set. When a high frequency signal inputted, the impedance of the removable collar approximate the impedance of the cable wire so that to reduce the reflected amount of the transmitting signal to achieve the purpose of matching high frequency impedance.

Therefore, the present invention provides a removable collar for matching high frequency impedance. The removable collar used for matching high frequency impedance disposed with a signal inputting port and a signal outputting port of a high frequency cable television device and disposed with a signal transmitting terminal of a cable wire, the removable collar includes a main body. The main body has an external surface, the external surface has a joint part for disposing with a signal inputting port and a signal outputting port. The central of the main body having a via hole, the via hole having an inner wall surface and a thick part formed between the external surface and the inner wall surface. The thick part has two symmetrical notches for allowing a tool to clamp thereon, and then the main body of the removable collar is disposed into the signal inputting port or the signal outputting port. When a high frequency signal is inputted, the impedance of the removable collar is substantially close to the impedance of the cable wire so that a reflected amount of the transmitting signal is reduced and an attenuation of the transmitting high frequency signal is reduced.

The present invention further includes a high frequency cable television device having removable collar, the high frequency television device includes a housing, the housing having a signal inputting port on one side of the housing and a signal outputting port on another side of the housing and opposite to the signal inputting port. A conductive bridge set is disposed within the housing and between the signal inputting part and the signal outputting part. Two symmetric assembling parts are disposed on a lateral plane which is adjacent to the signal inputting port and the signal outputting port and corresponding to the conductive bridge set disposed within the housing. The signal inputting part and the signal outputting port respectively has an assembling part having screw thread surface.

A removable collar is disposed in the signal inputting port or the signal outputting port. The removable collar includes a main body. The main body has an external surface, the external surface has a joint part for disposing with a signal inputting port and a signal outputting port. The central of the main body having a via hole, the via hole has an inner wall surface and a thick part formed between the external surface and the inner wall surface. The thick part has two symmetrical notches for allowing a tool to clamp thereon, and then the main body of the removable collar is disposed into the signal inputting port or the signal outputting port. A cable wire includes a core wire, a joint and a signal transmitting terminal. The joint 32 is plugged into the signal inputting port or the signal outputting port and passed through the removable collar. When a high frequency signal is inputted, the impedance of the removable collar is substantially close to the impedance of the cable wire so that a reflected amount of the transmitting signal is reduced and an attenuation of the transmitting high frequency signal is reduced.

BRIEF DESCRIPTION OF DRAWING

The features of the invention believed to be novel are set forth with particularity in the appended claims. The invention itself, however, may be best understood by reference to the following detailed description of the invention, which describes an exemplary embodiment of the invention, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a sectional view of a conventional cable television device;

FIG. 2 is a perspective view of a removable collar according to the present invention;

FIG. 3 is an exploded perspective view of the high frequency cable television device and the removable collar;

FIG. 4 is an assembly sectional view of the high frequency cable television device with removable collar;

FIG. 5 is a schematic view of the transmitting terminal penetrated through the removable collar;

FIG. 6 is another assembly sectional view of the high frequency cable television device with removable collar.

DETAILED DESCRIPTION OF THE INVENTION

A preferred embodiment of the present invention will be described with reference to the drawings. Reference is made to FIG. 2, which is a perspective view of a removable collar according to the present invention. The removable collar of the present invention is used for matching high frequency impedance. The removable collar has a main body 1 which is of circular cylinder shape and made of metallic material. The main body 1 has an external surface 11. The external surface 11 has a joint part 12 having screw thread for allowing the main body 11 disposing into a signal inputting port or a signal outputting port of a high frequency cable television device (not shown). Moreover, the external surface 11 may be one of smooth surface, arc surface and rough surface for allowing the removable collar disposing directly into the signal inputting port or the signal outputting port. Furthermore, a via hole 13 is penetrated into the center of the main body 1 for passing a signal transmitting terminal (not shown) through. Modulating the ratio of the diameter of via hole 13 to the diameter of the signal transmitting terminal or the permittivity (c) of the material for manufacturing the main body 11 can change the impedance of the removable collar and then achieve high frequency matching. The via hole 13 has an inner wall surface 14 and a thick part 15 is formed between the external surface 11 and the inner wall surface 14. The thick part 15 has two symmetrical notches 16 for allowing a tool (not shown) to clamp thereon, and then the main body 11 of the removable collar is disposed into the signal inputting port or the signal outputting port of the high frequency cable television device.

Reference is made to FIG. 3 and FIG. 4, which are an exploded perspective view and an assembly sectional view of the high frequency cable television device with removable collar. The high frequency cable television device 2 includes a housing 21, the housing 21 includes a tubular signal inputting part 22 at one side and a tubular signal outputting part 23 at another side. A conductive bridge set 24 is disposed within the housing 21 and between the signal inputting part 22 and the signal outputting part 23. The conductive bridge set 24 is used for transmitting signal inputted from the signal inputted port 22 to the high frequency cable television device 2. Two symmetric tubular assembling parts 25 are disposed on a lateral plane which is adjacent to the signal inputting port 22 and the signal outputting port 23 and corresponding to the conductive bridge set 24 disposed within the housing 21. The signal inputting part 22 (signal outputting port 23) has an assembling part 221 having screw thread surface for assembling the main body 1 of the removable collar and a cable wire 3. The cable wire 3 includes a core wire 31, a joint 32 and a signal transmitting terminal 33 penetrating the joint 32.

When assembling, the main body 1 of the removable collar is disposed into the signal inputting port 22 (or the signal outputting port 23), the signal transmitting terminal 33 of the joint 32 of the cable wire 3 is plugged into the signal inputting port 22 (or the signal outputting port 23) and passed through the via hole 13, so that the signal transmitting terminal 33 penetrates into conductive pins 241 of the conductive bridge set 24. And then, a smaller screw 26 penetrates into the assembling port 25 and threaded with the conductive pin 241 so that the signal transmitting terminal 33 is fastened to the conducted pins 241 of the conductive bridge set 24. Afterward, a larger screw 27 is threaded through the assembling port 25.

Reference is made to FIG. 4 and FIG. 5, which are a sectional view of the high frequency cable television device with the removable collar and a schematic view of the transmitting terminal penetrated through the removable collar. The cable wire 3 is connected to the signal inputting port 22 of the high frequency cable television device 2. When the signal inputted to the high frequency cable television device 2 (or the frequency of the high frequency signal is equal to or more than 1.0 GHz), the impedance of the removable collar is close to the impedance (Zo) (about 75±15 Ω) of the cable wire 3 so that the reflected amount of the transmitting signal is reduced and the attenuation of the transmitting high frequency signal is reduced to achieve the purpose of matching high frequency impedance.

The calculation of characteristic impedance (Zo) is shown below:

${Zo} = \sqrt{\frac{L}{C}}$ ${L\left( {{inductance}\mspace{14mu} {value}} \right)} = {\left( \frac{u}{2\pi} \right){\ln \left( \frac{b}{a} \right)}\mspace{14mu} \left( {H\text{/}m} \right)}$ ${C\left( {{capacitance}\mspace{14mu} {value}} \right)} = {\frac{2{\pi ɛ}}{\ln \left( \frac{b}{a} \right)}\mspace{14mu} \left( {F\text{/}m} \right)}$

Wherein a is the signal transmitting terminal 33, b is the via hole 13 of the removable collar, u is permeability and c is permittivity.

Referenced is made to FIG. 6, which is another assembly sectional view of the high frequency cable television device with removable collar. In this embodiment, the inner wall surface 14 of the main body 1 of the removable collar has an isolating layer 17 made of plastic material. The isolated layer 17 can prevent short circuit contact of the removable collar and the signal transmitting terminal 33 and ensure the signal transmission through the cable wire to the high frequency cable television device 2.

Although the present invention has been described with reference to the foregoing preferred embodiment, it will be understood that the invention is not limited to the details thereof. Various equivalent variations and modifications can still occur to those skilled in this art in view of the teachings of the present invention. Thus, all such variations and equivalent modifications are also embraced within the scope of the invention as defined in the appended claims. 

1. A removable collar used for matching high frequency impedance disposed with a signal inputting port and a signal outputting port of a high frequency cable television device and disposed with a signal transmitting terminal of a cable wire, the removable collar comprising: a main body having an external surface and a via hole allowing the signal transmitting terminal to penetrate, the via hole having an inner wall surface, and a thick part formed between the external surface and the inner wall surface; wherein, when a high frequency signal is inputted, the impedance of the removable collar is substantially close to the impedance of the cable wire so that a reflected amount of the transmitting signal is reduced and an attenuation of the transmitting high frequency signal is reduced.
 2. The removable collar in claim 1, wherein the main body is of circular cylinder shape and made of metallic material.
 3. The removable collar in claim 2, wherein the external surface comprising a joint part which is of one of screw shape, smooth surface, arc surface and rough surface.
 4. The removable collar in claim 1, wherein the impedance is 75±15 Ω.
 5. The removable collar in claim 4, wherein the high frequency characteristic impedance is calculated by the ratio of the diameter of the via hole of the main body and the diameter of the signal transmitting terminal.
 6. The removable collar in claim 4, wherein the high frequency characteristic impedance is calculated by the material permittivity of the main body.
 7. The removable collar in claim 3, wherein the thick part has two symmetrical notches.
 8. The removable collar in claim 5, wherein the inner wall surface of the main body has an isolated layer made of plastic material.
 9. A high frequency cable television device used for connecting a cable wire having a core wire, a joint and a signal transmitting terminal, the high frequency cable television device including: a housing having a signal inputting port on one side of the housing and a signal outputting port on another side of the housing and opposite to the signal inputting port; a removable collar disposed in the signal inputting port and the signal outputting port; wherein when the joint is connected to the signal inputting port or the signal outputting port, the signal transmitting terminal passes through the removable collar, when a high frequency signal is inputted, the impedance of the removable collar is substantially close to the impedance of the cable wire so that the reflected amount of the transmitting signal is reduced and the attenuation of the transmitting high frequency signal is reduced.
 10. The high frequency cable television device in claim 9, wherein a conductive bridge set is disposed in the housing and between the signal inputting port and the signal outputting port.
 11. The high frequency cable television device in claim 10, further comprising two symmetric assembling ports arranged on a lateral surface adjacent to the signal inputting port and the signal outputting port, and the assembling ports are corresponding to the conductive bridge set disposed within the housing.
 12. The high frequency cable television device in claim 11, wherein the signal inputting port and the signal outputting port have an assembling part with screw surface, respectively.
 13. The high frequency cable television device in claim 12, wherein the removable collar comprises a main body, the main body comprising an external surface and a through hole, the through hole has an inner wall surface, a thick part being formed between the external surface and the inner wall surface.
 14. The high frequency cable television device in claim 13, wherein the main body is of circular cylinder shape and made of metallic material.
 15. The high frequency cable television device in claim 9, wherein the impedance is 75±15 Ω.
 16. The high frequency cable television device in claim 14, wherein the high frequency characteristic impedance is calculated by the ratio of the diameter of the via hole of the main body and the diameter of the signal transmitting terminal.
 17. The high frequency cable television device in claim 13, wherein the high frequency characteristic impedance is calculated by the material permittivity of the main body.
 18. The high frequency cable television device in claim 14, wherein the external surface has a joint part which is of one of screw shape, smooth surface, arc surface and rough surface.
 19. The high frequency cable television device in claim 18, wherein the thick part has two symmetrical notches.
 20. The high frequency cable television device in claim 19, wherein the inner surface of the main body has an isolating layer made of plastic material. 